Significant progress has been made in the treatment of certain cancers, and the prognosis for individuals with some types of cancers, such as prostate, breast, thyroid, and skin cancer (i.e., certain melanomas) is generally good for at least 4 out of 5 patients. According to the United States National Institutes of Health, however, the prognosis for individuals with cancers such as those of the brain (27.3% survival), lung (13.4% survival), liver (6.0% survival), and pancreas (3.2% survival) has been poor, based upon statistics compiled from 1983 to 1990. According to the American Cancer Society, almost 22,000 people in the United States alone develop brain and nervous system cancers each year, and about 13,070 people die from these cancers. About 42 percent of all brain tumors are gliomas. Grade IV astrocytoma (glioblastoma multiforme, or GBM), for example, is considered by many to be the most malignant brain tumor. The average length of survival for people with GBM is 12 to 14 months, and common symptoms of GBM are seizures, nausea and vomiting, headaches that become progressively worse, a declining ability to move certain parts of the body, and weakness or numbness in the face or arm. GBM rapidly affects the quality of the patient's life, and it may affect individuals of any age.
Discovering and developing effective therapeutic agents for difficult-to-treat cancers is important both for the benefit of individuals who are diagnosed with those cancers, as well as for individuals who may have other difficult-to-treat forms of cancer. For example, researchers at the University of Minnesota's Masonic Cancer Center have discovered a genetic link between two types of cancers for which effective treatment has been achieved in only a small fraction of the individuals diagnosed with those cancers—glioblastoma and leukemia. Agents that are found to effectively treat one form of these difficult cancers may therefore provide excellent lead compounds for testing as therapeutic agents for other cancers which are known to be more refractory to treatment. What are needed are agents that effectively treat cancers and provide increased life expectancy and quality of life for thousands of individuals who are diagnosed with cancer each year.